1. Field of the Invention
The invention relates to a coextruded, multilayered, biaxially oriented, weldable flat film used to produce tubular films by welding in a well-known manner, which tubular films are used for the packaging and wrapping of foodstuffs, particularly pasty foodstuffs.
2. Description of the Background
Multilayered, biaxially oriented flat films produced either by coextruding a tubular film and cutting open the tube, or by direct coextrusion of a flat film are well-known. Using welding for packaging purposes, all kinds of tubular films can be produced from such multilayered flat films in a well-known fashion by bending the flat film to form a tube and joining the contacting opposite edges by a seal strip extending in longitudinal direction. A second way would be bending the flat film to form a tube by allowing overlap of the opposite edges and welding together the overlapping areas. A third way of forming a tubular film from a flat film is bending the flat film to form a tubular film and welding together the respective opposite edge areas along the length thereof, thereby forming a longitudinal fold where equal sides of the flat film make contact with each other.
In addition to high impermeability to water vapor and oxygen, such films must meet high demands with respect to weldability and, in particular, strength of the weld seam.